Observational ocean acoustics as a window to the anthropocene

In a time of rapid ocean environmental change, study of ambient noise is emerging as one of the most powerful techniques for understanding human impacts on the ocean-climate system. Perception of how marine organisms of all types utilize sound and respond to patterns and anomalies in ambient noise facilitates a transformative understanding of the ocean environment for exploration, discovery, climate impact assessment, and national defense. Considering ocean acoustics alongside established marine ecology and physical oceanography data sets and methodologies has led to improved characterization of marine biological sound sources; observations of biological aggregations structuring around and producing ambient noise sources; and linkages between diel, lunar, and interannual cycles and ambient noise levels. Long-term ambient noise monitoring shows correlations not only with light levels from solar and lunar sources, but ocean temperature as we continue to experience surface ocean warming. Observational acoustical oceanographic methods offer new opportunities to understand global anthropogenic change effects as well as to hone in on meso- to sub-meso-scale oceanographic variability influenced by biology that is often not well resolved in models.